1. Field of Disclosure
The present disclosure relates to improvements in bar code symbol reading systems employing laser scanning patterns having improved characteristics.
2. Brief Description of the State of Knowledge in the Art
Bi-optic laser scanners require the projection of several scan lines at multiple angles and directions to ensure code coverage and increased probability of a successful scan. A raster pattern can be generated in such a way that multiply the parallel scan lines of the raster scanning pattern. This is typically accomplished using multi-faceted reflective polygons that include various facet angles. For each additional raster line, scan performance will likely increase.
U.S. Pat. No. 7,077,324 to Tien discloses a multi-line raster-type barcode laser scanner with no moving parts. The laser scanner includes a light source, a light condensing lens and a linear light receiver. The system employs at least one beam splitter and reflectors disposed at the projecting path from the light source converted into scanning light beam to the barcode, so as to enable the scanner to project two or more scanning light beams onto a same barcode in a non-overlapping manner. This enables the selection of a complete barcode image for decoding at a fastest speed and for further increasing the barcode reading rate from the barcode at different angles or positions.
However, the number of scan lines in the raster pattern of U.S. Pat. No. 7,077,324 is limited to the number of beam splitters and reflectors which complicates the design and increases manufacturing costs.
Thus, there is a great need for improvement in the method of and apparatus for generating a multiple-type raster scanning pattern for scanning bar code symbols with increased scanning speed and read rates, while avoiding the shortcomings and drawbacks of prior art apparatus and methodologies.